The present invention relates to an apparatus for providing a visual navigation interface through the use of a real-time volume rendering of large-scale volume data.
The present invention generates 3D images through the use of a 3-dimensional (3D) graphics technology based on volume data used in various fields such as medical images, computer graphics, virtual reality and scientific data visualization. The 3D images are used in a diagnosis, a medical simulation and so on in the case when using the medical data. In the computer graphics and virtual reality fields, the images are used in the modeling of complex objects, the visualization of a natural phenomenon, or the like.
In the event of the scientific volume data, the images are also used in a weather forecast or an oceanic and geological observation.
The volume data used in the above arts are becoming more accurate by the development of measure equipment, calculation methods and the like and are generated in the large-scaled form.
Accordingly, there have been proposed various schemes and devices for generating the 3D images based on the volume data.
Among them, there is a scheme which generates polygon data, treatable in conventional graphics display devices, from the volume data and produces the images by using the conventional graphics devices from the polygon data. There is a scheme, i.e., a volume rendering scheme, which generates the images by synthesizing internal values of the volume data along a straight line penetrating the volume data on a plain displaying the 3D images, without generating the polygon data.
The above volume rendering can obtain a more realistic image compared to the former scheme and display an internal structure of an object together with its surface. However, since this volume rendering cannot be used in the conventional graphics apparatus, there is a disadvantage that the rendering time is long.
Therefore, there have been developed various schemes and apparatus so as to reduce the rendering time. The present invention is used in the same manner as the apparatus, employing a 3D texture memory, among apparatus for performing real-time volume rendering in its usage co-operate. But, unlike to the conventional apparatus, the present invention has a different scheme for constituting the texture memory and co-operates with a compression/decompression device.
The aforementioned real-time volume rendering apparatus are sufficiently adopted to their applications in the case of a relatively small amount of volume data. However, they cannot provide the performance required to visualize a large-scale volume data recently being developed.
Therefore, nowadays, there is developing techniques for compressing the large-scale volume data into an amount of data that the existing apparatus can process and performing the rendering by using the compressed volume data, and, among the techniques, there are vector quantization, sub-band coding, wavelet, DCT and the like.
It is, therefore, a primary object of the present invention to provide an apparatus for compressing a large amount of volume data that the existing volume rendering accelerating device and graphic display device cannot process, storing the compressed volume data and variably using the volume data in the rendering according to various conditions such as real-time volume rendering, the specific resolution of one data within the volumes in an image coordinate plane, a location at which an image is generated and a distance between volume data.
In accordance with the present invention, there is provided an apparatus for performing a real-time rendering capable of interacting with a user to visualize internal information of a large-scale 3 dimensional (3D) volume data, comprising: a large capacity storing device for generating multi-resolution models by filtering the large-scale volume data, compressing the generated multi-resolution models and storing the compressed models; a memory for caching block volume data for a portion of all of the volumes which are required in the rendering; and a 3D texturing system for generating a 3D rendered image with the volume compression and decompression device through the memory.
Further, the present invention provides an interfacing method and an apparatus capable of making a user accomplish a visual navigation by real-time rendering compressed 3D DCT volume data through the co-operation with a 3D texture memory and a device employing a compression/decompression scheme which extends DCT to a 3 dimension and applies the extended 3D DCT to the volume data.